On December 20, 2018, MPCA issued PolyMet a final synthetic minor permit for the NorthMet Mine that reflected an extensive permitting process and resulted in 1,020 requirements designed to ensure the facility’s air emissions remain below major source levels.
Earlier this summer, the Minnesota Court of Appeals directed the MPCA to explain further its decision-making under Minnesota air permitting and to address documents submitted to the agency in 2018 that discuss potential expansion scenarios. The Court of Appeals did not direct MPCA to reopen the administrative record, and the agency will not be accepting new information.
Within the next 60 days, the MPCA will review the administrative record materials, including those supplemented by the court, consistent with the Court of Appeal’s remand.
An air emission permit is a regulatory document that contains legally enforceable requirements. A permit identifies the units at each facility that generate air pollutants, details the conditions under which the facility must operate to comply with rules and regulations and, where applicable, sets limits on those emissions.
The MPCA follows the general process below for processing air permits applications:
The public comment period for the draft air emission permit for PolyMet's NorthMet project was January 31, 2018 to March 16, 2018. The MPCA reviewed and considered comments received which resulted in changes to the draft permit. The MPCA submitted a proposed permit and support documents to the Environmental Protection Agency (EPA) for review on October 25, 2018. The MPCA issued the final air emission permit on December 20, 2018.
FINAL PolyMet Air Quality Permit - Permit (aq5-36w)
FINAL PolyMet Air Quality Permit - Appendices (aq5-36x)
FINAL PolyMet Air Quality Permit - TSD (aq5-36y)
FINAL PolyMet Air Quality Permit - TSD Attachments (aq5-36z)
FINAL PolyMet Air Quality Permit Response to Comments (aq5-36aa)
FINAL PolyMet Air Quality Permit Order (aq5-36bb)
The State’s Title V air permitting program allows the public to petition the EPA administrator to object to specific permits. Petitions must be filed with the EPA Administrator within 60 days after the EPA review period concludes. The 60-day petition period for the PolyMet air permit begins on December 11, 2018 and ends on February 11, 2019.
Public notice and public meetings
MPCA staff completed their review of the updated permit application and supporting materials and prepared a draft permit and supporting fact sheet for the proposed project. The draft permit and fact sheet were provided to the interested Tribes, the EPA, and the Permittee for an early review and comment period on January 24, 2018. The public notice period for the draft permit ran from January 31, 2018 to March 16, 2018. The MPCA held two public meetings on the draft permits jointly with the Minnesota Department of Natural Resources on Wednesday, February 7, 2018 in Aurora and Thursday February 8, 2018 in Duluth.
Public notice, draft permit, and technical support documents:
PolyMet Air Quality Permit Public Notice
Draft Air Emissions Permit No. 13700345-101
Draft TSD for Air Emissions Permit No. 13700345-101
Draft TSD Attachments for Air Emissions Permit No. 13700345-101
Permit application submitted
On August 24, 2017, PolyMet submitted an air permit application to the Minnesota Pollution Control Agency (MPCA) for its proposed NorthMet project in northeastern Minnesota. The information contained in these documents helps the MPCA determine which state and federal requirements apply and develop conditions for a permit that ensures the project can meet applicable laws and requirements. During this process it is normal for MPCA technical staff to request additional information from the applicant.
Previous supporting documents
Public meeting fact sheets
Overview of PolyMet’s air permit (aq5-36q) (Feb 2018)
PolyMet’s mercury air emissions (aq5-36r) (Feb 2018)
Fiber requirements in the PolyMet air permit (aq5-36s) (Feb 2018)
Air Modeling Protocol Review
Before PolyMet can submit an air permit application, they must conduct air quality modeling to estimate potential air quality impacts. Before an applicant completes the modeling, they must have a modeling protocol approved by the MPCA. The air quality modeling protocol describes the modeling approach and data that will be used to predict pollutant concentrations. The modeling results must be submitted with a permit application.
Class I Air Modeling
Class I areas are places where air quality is given special protections. PolyMet is near four Class I areas: Boundary Water Canoe Area Wilderness, Voyageurs National Park, Isle Royale National Park, and Rainbow Lake Wilderness. Class I modeling is conducted to estimate the potential impact on these areas.
The results of the Class I modeling, based on the modeling protocol, are included in a permit application.
Class II Air Modeling
Class II areas are places where the air quality meets all standards and moderate increases in air quality impacts are allowed. All of Minnesota, except for the Boundary Water Canoe Area Wilderness and Voyageurs National Park, is designated as Class II. Class II modeling is conducted to estimate the potential impact in Class II areas near the proposed facility.
The results of the Class II modeling, based on the modeling protocol, are included in a permit application.
Air Emissions Risk Analysis (AERA) Modeling
An AERA uses a scientific process to estimate the potential human health risks from air toxics, pollutants that may cause cancer, other serious health effects, or environmental and ecological effects. The quantitative risk estimates and qualitative information, for both the facility and the surrounding area, are meant to describe risks to individuals who, as a result of where they may live and what they do, may experience the highest level of exposure within a reasonable set of situations.
The results of the AERA modeling, based on the work plan, are included in a permit application.
Permit application documents submitted by Polymet
Application for a Permit to Construct and Operate v1 AUG2016-1.pdf
Application for a Permit to Construct and Operate v1 AUG2016-2.pdf
Application for a Permit to Construct and Operate v1 AUG2016-3.pdf
PolyMet Air Permit Application v2-Part 1 (aq5-35t) (1-11-2018)
PolyMet Air Permit Application v2-Part 2-Appendices (aq5-35u) (1-11-2018)
PolyMet Air Permit Application v2-Part 3-Appendices (aq5-35v) (1-11-2018)
PolyMet Air Permit Application v2-Part 4-Appendices (aq5-35w) (1-11-2018)
PolyMet Air Permit Application v2-Part 5-Appendices (aq5-35x) (1-11-2018)
Air quality permit applications include a description of:
- equipment at the facility that will generate air pollutants
- pollution control equipment that will be used to reduce emissions
- type and quantity of air pollutants that will be emitted
- potential air quality impacts near the facility
In addition to the application documents above, PolyMet submitted the studies, reports, and other documents referenced in the application and air modeling output files. Because of the volume, size, and format of these files they are not posted online but are available by request at https://www.pca.state.mn.us/about-mpca/information-requests
PolyMet Class I report erratum (aq5-35) (12/23/2016)
PolyMet AERA report erratum (aq5-35a) (1/10/2017)
PolyMet Class I modeling approval (2/8/2017)
PolyMet Mine Site Fugitive Emissions Control Plan (aq5-35c) (4/14/2017)
PolyMet Plant Site Fugitive Emissions Control Plan (aq5-35d) (4/14/2017)
PolyMet Fiber Monitoring and Quality Assurance Project Plan (aq5-35e) (8/31/2017)
PolyMet AERA Emissions Technical Memo Update V2 (aq5-35f) (09/17/2017)
PolyMet AERA Emissions True-Up Technical Memo v1d2 (aq5-35g) (10/5/2017)
PolyMet AERA Errata and Response to Comments (aq5-35h) (12/19/2016)
PolyMet AERA Forms v1 NOV 2016 (aq5-35i) (08/24/2016)
PolyMet AERA Mine Site Update v1 NOV 2017 (aq5-35j) (11/15/2017)
PolyMet AERA Proposed Verification v1 FEB 2017 (aq5-35k) (02/22/2017)
PolyMet AERA Risk Analysis and Respirable Fraction of Dust Based Emissions v2 JUL 2012 (aq5-35l) (07/18/2012)
PolyMet AERA Verification Runs v1 MAY 2017 (aq5-35m) (05/30/2017)
PolyMet AERA MDH MPCA Memo NOV 2014 (aq5-35n) (11/20/2014)
PolyMet AERA 1Hr Results value Cu Ni fix with As (aq5-35o) (12/06/2017)
PolyMet AERA 2017 RASS Mine Site multipathway year 8 (aq5-35p) (2/06/2017)
PolyMet AERA 2017 RASS Mine Site multipathway year 13 (aq5-35q) (12/06/2017)
PolyMet AERA 2017 RASS Plant Site Inhale RME Cancer Chronic CuNiFix (aq5-35r) (12/06/2017)
PolyMet AERA 2017 RASS Plant Site Inhale RME Non Cancer Chronic CuNiFix (aq5-35s) (12/06/2017)
PolyMet Class II 1 Hour NO2 NAAQS Cumulative Results (aq5-36l) (12/01/2017)
PolyMet Class II 1 Hour PM2.5 NAAQS Cumulative Results-Year 8 (aq5-36m) (12/01/2017)
PolyMet Class II 1 Hour SO2 NAAQS Cumulative Results (aq5-36n) (12/01/2017)
PolyMet Class II 24-Hour PM2.5 NAAQS Cumulative Results-Year 13 (aq5-36o) (12/01/2017)
PolyMet Class II 24-Hour PM10 NAAQS Cumulative Results-Year 8 (aq5-36p) (12/01/2017)
PolyMet Class II 24-Hour PM10 NAAQS Cumulative Results-Year 13 (aq5-35y) (12/01/2017)
PolyMet Class II Annual PM2.5 NAAQS Cumulative Results-Year 8 (aq5-35z) (12/01/2017)
PolyMet Class II Annual PM2.5 NAAQS Cumulative Results-Year 13 (aq5-36a) (12/01/2017)
PolyMet Class II AQDM Results Form DEC 2017 (aq5-36b) (12/01/2017)
PolyMet Class II AQDM Results Review Form DEC 2017 (aq5-36c) (12/14/2017)
PolyMet Class II Cumulative NAAQS Receptor Grid (aq5-36d) (12/01/2017)
PolyMet Class II Mine Site Model Source Layout-Year 8 (aq5-36e) (12/01/2017)
PolyMet Class II Mine Site Model Source Layout-Year 13 (aq5-36f) (12/01/2017)
PolyMet Class II Modeling Analysis Memo-DEC 2017 (aq5-36g) (12/01/2017)
PolyMet Class II Process Plant Model Source Layout (aq5-36h) (12/01/2017)
PolyMet Class II Tailings Basin Model Source Layout (aq5-36i) (12/01/2017)
PolyMet Class I Air Quality Dispersion Modeling Report JAN 2018 (aq5-36j) (12/23/2016)
PolyMet Class I Air Quality Dispersion Modeling Report Review Form JAN 2018 (aq5-36k) (02/01/2017)
On September 1, 2016, MPCA provided PolyMet with a letter indicating that the air quality permit application for its proposed NorthMet project was determined to be ‘complete enough for processing.’ MPCA staff may have additional questions during the development of the permit to clarify information contained in the application and may request additional information from PolyMet to address these questions. These requests will not invalidate the determination of completeness for this application. This letter is not an approval to construct, modify, or operate the facility.
Public input will be solicited if a draft permit is developed. The MPCA encourages public participation during the formal public notice and comment period.
Tribal and Permittee Review
On August 24, 2016, PolyMet submitted an application to the MPCA for an air quality permit for its proposed NorthMet mining project in northeastern Minnesota. MPCA staff processed the application and began preparing a draft permit. This resulted in additional information and clarifications being made to the Agency. To reflect this additional information, PolyMet submitted an updated version of the permit application in January 2018.
MPCA staff have completed their review of the permit application and supporting materials and have prepared a draft permit and supporting technical support document for the proposed project. The draft permit and technical support were provided to the interested Tribes and PolyMet for their review. A formal public notice and comment period, during which the public meetings identified above will take place, will follow. The MPCA encourages public participation during the formal public notice and comment period.
More on air permitting
- General information about air permits
- Examples of permits issued in Minnesota
- Information about air modeling
- Information about AERAs
- Public participation in the air permitting process: Citizens' Guide to Part 70 (Title V) Air Quality Permits [06/2010]